SAN FRANCISCO— The Center for Biological Diversity today filed a legal petition urging the Environmental Protection Agency to stop oil and gas companies from dumping toxic chemicals from fracking directly into ocean waters off California.

About half the oil platforms in the Santa Barbara Channel discharge some or all of their wastewater into the sea. The oil industry has federal permission to dump more than 9 billion gallons of wastewater a year directly into the ocean off California’s coast.

“It’s disgusting that oil companies dump wastewater into California’s ocean,” said Miyoko Sakashita, oceans director at the Center. “You can see the rigs from shore, but the contaminated waters are hidden from view. Our goal is to make sure toxic fracking chemicals don’t poison wildlife or end up in the food chain.”

Today’s petition urges the EPA to modify an existing federal permit that allows offshore oil and gas operations to pollute the ocean with dangerous wastewater. Such wastewater may contain fracking chemicals used in offshore wells. The petition also calls on the EPA to develop national guidelines for offshore fracking pollution.

Oil companies have hydraulically fractured more than a dozen wells in recent years in federal waters off California, where the EPA permits wastewater discharge. At least 200 wells in state waters have also been fracked.

A recent Center analysis of 12 frack jobs in state waters found that at least one-third of chemicals used in these fracking operations are suspected ecological hazards. Drawing on data disclosed by oil companies, the Center also found that more than a third of these chemicals are suspected of affecting human developmental and nervous systems.

“It came as a complete surprise to learn that oil companies are fracking in waters off the coast where I let my kids swim and play,” said Sakashita. “The toxic chemicals used for offshore fracking don’t belong in the ocean, and the best way to protect our coast is to ban fracking altogether.”

Staff experts with the California Coastal Commission recently recommended an end to ocean discharges, citing concerns about the danger to California’s coastal environment from dumping of fracking and acidizing chemicals from offshore oil wells into federal waters.

The Center for Biological Diversity is a national, nonprofit conservation organization with more than 675,000 members and online activists dedicated to the protection of endangered species and wild places.